4 belongs to any set that contains it. So {1, pi, 4, -37.5689, sqrt(2)} is a possible answer.
To any set that contains it! It belongs to {23.5}, or {23.5, sqrt(2), pi, -3/7}, or all whole numbers between 13 and 53, or integer multiples of 0.5, or rational numbers, or real numbers, or complex numbers, etc.
It belongs to the interval (25, 27.3), or [-20.9, 10*pi], and infinitely more such intervals.It also belongs to the set of rational numbers, real numbers, complex numbers and quaternions.
To any set that contains it! It belongs to {1.18}, or {45, sqrt(2), pi, 1.18, -3/7}, or all numbers between -2 and 453, or improper fractions (1.18 = 19/50], or rational numbers, or real numbers, or complex numbers, etc.
Irrational numbers.
The set of numbers which 3 does not belong is the set of even numbers.
It belongs to any set which contains it. For example: {-21} {pi, yellow, -21, Germany} {numbers smaller than -17}
4 belongs to any set that contains it. So {1, pi, 4, -37.5689, sqrt(2)} is a possible answer.
Any set of numbers that contain them! For example, they belong to the set {10, 11} or {10, 11, sqrt(2), pi, -3/7}, or {10, 11, bananas, France, cold} or all whole numbers between 3 and 53, or counting numbers, or integers, or rational numbers, or real numbers, or complex numbers, etc.
Pi is an Irrational number, which is one of the two subcategories of real numbers.
Pi is both an irrational number and a transcendental number.
To any set that contains it! It belongs to {5.385164807}, or {45, sqrt(2), pi, 5.385164807, -3/7}, or all numbers between 4 and 53, or rational numbers, or real numbers, or complex numbers, etc.
10 belongs to the set "natural numbers", but it can also belong to whole numbers, and rational numbers
To any set that contains it! It belongs to {23.5}, or {23.5, sqrt(2), pi, -3/7}, or all whole numbers between 13 and 53, or integer multiples of 0.5, or rational numbers, or real numbers, or complex numbers, etc.
To any set that contains it! It belongs to {0.25}, or {45, sqrt(2), pi, -3/7, 0.25}, or multiples of 0.05, or fractions between 0 and 1, or reciprocals, or rational numbers, or real numbers, or complex numbers, etc.
If you're talking about real numbers, then it is an irrational number. Any number that cannot be written as a fraction is irrational. You cannot write pi as a fraction (22/7 is just an estimate). So any thing multiplied with pi cannot be rational either.
To any set that contains it! It belongs to {45}, or {45, sqrt(2), pi, -3/7}, or all whole numbers between 43 and 53, or multiples of 5, or composite numbers, or counting numbers, or integers, or rational numbers, or real numbers, or complex numbers, etc.